What is the busiest airport in the world? (by number of passengers)

London Heathrow
694
Hartsfield–Jackson Atlanta International Airport
558
Beijing Capital International Airport
325
Dubai International Airport
629
Hartsfield–Jackson, is an international airport located 11 km south of Atlanta's central business district, in the U.S. state of Georgia. In 2012 it was the busiest airport in the world accommodating 100 million passengers (more than 260,000 passengers daily) and 950,119 flights.
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